Antidepressants May Affect Miscarriage Risk

< Jun. 02, 2010 > -- New research from Canada suggests that women who take a certain type of antidepressant during pregnancy may increase their risk of having a miscarriage by 68 percent.

Up to 20 percent - or one woman out of five - will suffer a miscarriage for various reasons during pregnancy. But research study results suggest that a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs) may increase that risk, according to lead researcher Anick Berard, Ph.D., an associate professor at the University of Montreal.

Antidepressant use is common during pregnancy, with up to 3.7 percent of women taking the medications during the first trimester. Stopping treatment can lead to a return of depression and other symptoms. Previous studies of the medications' effects on the fetus have been small and had contradictory results.

But the Canadian case-control study on more than 5,000 women found that by controlling for other factors associated with miscarriage, taking SSRIs during pregnancy led to an increased risk of miscarriage.

Study Details Revealed

Dr. Berard's team collected data on 5,124 women who had clinically verified miscarriages and compared them with another group of women who had not miscarried.

The researchers found that 5.5 percent of the women who had miscarriages were taking an antidepressant during their pregnancy.

The most commonly-used antidepressants were SSRIs. Among these, paroxetine (Paxil) and venlafaxine (Effexor) were associated with a 51 percent increased risk of miscarriage, Dr. Berard says.

The risk of miscarriage also increased with higher daily doses of these drugs. In addition, using a combination of different antidepressants doubled the risk of miscarriage, the researchers note.

Is Medication the Cause or Depression?

Dr. Berard says the study results "are highly robust given the large number of users studied." The results are published this week in the Canadian Medical Association Journal.

In addition, she says, the study makes clear that the medications, rather than the mothers' depression and anxiety, are associated with an increased risk for miscarriage.

However, the author of an editorial accompanying the research article noted that the finding is far from definitive.

"This is an association, not a cause," says Adrienne Einarson, RN, assistant director of the Motherisk Program at the Hospital for Sick Children in Toronto. "We still don't know if it's the depression or the drug."

Also, the risk uncovered by the study is a very small one, Einarson adds. "Less than twice as many women had miscarriages in the group with antidepressants as those who did not take antidepressants. It's a very small risk indeed, and it's not a reason to stop taking an antidepressant if you need it."

Women Should Discuss with Their Physician

Dr. Berard believes that as part of pregnancy planning, women should discuss with their physician the risks and benefits associated with different types of antidepressants.

"I would certainly advise against using Paxil and Effexor early on in pregnancy," she says. "This doesn't mean women can't use antidepressants; there are others on the market. Planning pregnancy and actually choosing which type of therapy beforehand is an option."

Einarson notes that many women with depression are undertreated. She says, "My bottom, bottom, bottom line is that if a woman needs to be on an antidepressant, she must continue to take it. This should not be a reason to stop it."

Another expert, Dr. Salih Yasin, associate professor and vice chair of obstetrics and gynecology at the University of Miami Miller School of Medicine, says this study can be useful in guiding physicians in advising patients.

First, one should determine whether the woman should be taking an antidepressant or not, Dr. Yasin notes. "There are many people who have depression, but don't need medication," he says.

"With patients who need medications, one has to pick the lowest dose of the ones that have the least association with miscarriage," says Dr. Yasin.

Always consult your physician or other healthcare provider for more information.

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More About Miscarriage

Miscarriage is usually defined as an early pregnancy loss. Miscarriage is also called spontaneous abortion. Types of miscarriage include the following:

threatened - spotting or bleeding in the first trimester may or may not mean a miscarriage will occur. About 10 to 20 percent of women will miscarry in the first trimester. The woman is monitored for further bleeding. Ultrasound exams (a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs) are usually performed to monitor growth of the fetus.

complete - the fetus, placenta, and other tissues are passed with bleeding.

incomplete - only a part of the tissues are passed. Some remain in the uterus. There may be heavy vaginal bleeding.

missed abortion - the embryo or fetus dies, but is not passed out of the uterus. Sometimes, dark brown spotting occurs, but there is no fetal heartbeat or growth.

septic - miscarriage that becomes infected, the mother develops fever and may have bleeding and discharge with a foul odor. Abdominal pain is common. This is a serious condition and can result in shock and organ failure if not treated. Antibiotics and dilation and curettage (D & C) may be necessary. This procedure uses special instruments to remove the abnormal pregnancy.

repeated - two or more miscarriages in a row.

recurrent - more than three miscarriages in a row.

Fetal loss in the second trimester may occur when the cervix is weak and opens too early, called incompetent cervix. In some cases of incompetent cervix, a physician can help prevent pregnancy loss by suturing the cervix closed until delivery - this procedure is called a cerclage.

The most common signs of miscarriage are vaginal spotting or bleeding, passing of tissue, and cramping. Ultrasound is usually used to diagnose miscarriage. If the fetus is no longer in the uterus, or there is no longer a fetal heartbeat, miscarriage is diagnosed. Other tests that may be used include pregnancy blood tests for the hormone human chorionic gonadotrophin (hCG). No increase in this hormone level or a decrease can indicate that the pregnancy is not growing.

Treatment for miscarriage in early pregnancy includes a procedure to remove the fetus and other tissues if they have not all been naturally passed. The procedure is called a surgical evacuation of the uterus, or a dilatation and curettage (D&C). Anesthesia is used as the procedure can be painful to the mother. The cervical opening is dilated (opened) and either suction or an instrument called a curette is used to remove all the pregnancy tissues inside the uterus (called products of conception). These tissues may be sent to the laboratory for culture or testing for genetic or chromosomal abnormalities.

Later pregnancy loss may need a different procedure using hormones such as prostaglandin or Pitocin to cause the uterus to contract and push out the fetus and tissues.

Pregnancy loss does not usually cause other serious medical problems, unless an infection is present, or unless a missed abortion occurred in which the fetus and other tissues are not passed. A serious complication with a late miscarriage is disseminated intravascular coagulation (DIC), a severe blood clotting problem. This is more likely if there is a long time (usually a month or more) until the fetus and other tissues are passed.

Always consult your physician or other healthcare provider for more information.